This invention relates to a device which can be implanted within an eye in order to replace some of the functions formerly performed by a surgically-removed vitreous body, and possibly also the zonular ligaments and lens. Zonular ligaments hold the lens in a useful position on the visual axis of the eye, and the lens focusses light on the retina of the eye.
The vitreous body of an eye is made up of connective tissue substances, fibres and cells, and is the practically-transparent jelly-like object which occupies the posterior cavity in the eye. It has a surface layer next to the retina, which surface layer serves as a barrier to rapid passage of fluid into holes which may exist in the retina, thus preventing retinal detachment developing in locations where a retinal hole exists. The vitreous body thus effectively closes any holes which may develop in the retina. When the vitreous surface layer detaches from the retina, which occurs with age, after certain injuries, and in certain disease states, it is then more likely that any retinal holes which may be present, or which may develop later, will become associated with retinal detachment, a disease state which leads to loss of function of the photographic-film-like layer of nerve tissue lining the eyeball.
For retinal re-attachment surgery to be effective in the long term, retinal holes must be closed, so that fluid cannot pass through them, and new holes which tend to develop in certain eyes predisposed to develop retinal detachments must be closed by some means which prevents fluid flow through them.
One problem facing retinal surgeons is proliferative vitreoretinopathy, which requires surgical removal of the vitreous body before the retina may be re-attached. Existing methods of closing holes by scleral buckling in towards the inside of the eye, or internal tamponade with gas bubbles (whose effect lasts at most two weeks or so), or silicone oil injection (which can cause corneal edema and other complications) are not effective for the remainder of the patient's life in all cases.
In eyes which require internal tamponade with silicone oil, cataract not infrequently develops, and lenses are not infrequently removed from eyes with vitreous surgery, so some eyes lack both a lens and vitreous body.
The aim of the invention is to provide a vitreous body prosthesis device which can carry out the retinal hole closing functions of the vitreous body of an eye after this body has been removed during retinal re-attachment surgery.